More Like this

1. Drivers of ecosystem vulnerability to Corbicula invasions in southeastern North America

   https://doi.org/10.1007/s10530-022-02751-4  

   Ferreira-Rodríguez, Noé ; Gangloff, Michael ; Shafer, Gregory ; Atkinson, Carla L. ( February 2022 , Biological Invasions)

   Invasive species introduction is one of the major ongoing ecological global crises. Identifying factors responsible for the success of invasive species is key for the implementation of effective management actions. The invasive filter-feeding bivalve,Corbicula, is of particular interest because it has become ubiquitous in many river basins across North America and elsewhere. Here we sampled bivalve assemblages, environmental indicators, and land cover parameters in the Ouachita highlands in southeastern Oklahoma and southwestern Arkansas, and in the Gulf Coastal Plain of Alabama to test three working models (using structural equation modeling, SEM) based on a priori scientific knowledge regardingCorbiculainvasions. Our models tested three competing hypotheses: (1) Native mussel declines are related to land use changes at the watershed level and subsequentCorbiculacolonization is a result of an empty niche; (2)Corbiculaabundance is one of the factors responsible for native mussel declines and has an interactive effect with land use change at the watershed level; (3) Native mussel declines andCorbiculasuccess are both related to land use changes at the watershed level. We found no evidence for the first two hypotheses. However, we found that environmental indicators and land cover parameters at the watershed scale were robust predictors ofCorbiculaabundance. In particular, agricultural land covermore »was positively related withCorbiculadensity. These results suggest that further improvement of conventional agricultural practices including the optimization of fertilizer delivery systems may represent an opportunity to manage this species by limiting nutrient inputs to stream ecosystems. Preservation of extensive floodplain habitats may help buffer these inputs by providing key ecosystem services including sediment and nutrient retention.

   « less
2. Changes in fish assemblages after marine heatwave events in West Hawai‘i Island

   https://doi.org/10.3354/meps14156  

   Olsen, AY ; Larson, S ; Padilla-Gamiño, JL ; Klinger, T ( October 2022 , Marine Ecology Progress Series)

   Marine heatwaves are prolonged events of anomalously warm water that affect diverse marine habitats and their associated biota. Evidence shows that anthropogenic climate change is increasing the frequency and duration of marine heatwaves and that coral reef systems are sensitive to the thermal stress imposed by these heatwaves. In this study, we examined fish community response to consecutive marine heatwaves (2014-2015) by analyzing changes in fish assemblages in Hawai‘i over 11 yr (2009-2019). Subtidal video survey data were collected in 3 areas on the west side of the Big Island of Hawai‘i. Fish were counted and identified to species or genus, then assigned to one of 7 functional groups: predators, secondary consumers, planktivores, corallivores, scrapers, grazers or browsers. Our study revealed 4 key findings. We show that all fish assemblages changed significantly in each area after the marine heatwaves. Across all 3 areas, the 3 most abundant functional groups (planktivores, grazers and secondary consumers) drove the observed changes in the community. Following the marine heatwaves, fish abundance increased in 2 areas with fewer fishing regulations. In the most protected area, fish abundance remained high and diversity indices were significantly higher post-marine heatwaves. Our results support the hypothesis that marine heatwavesmore »can cause shifts in fish assemblages and that the precise nature of these shifts can vary over relatively short spatial scales that may coincide with scales of management.« less
3. Emerging threats and persistent conservation challenges for freshwater biodiversity

   https://doi.org/10.1111/brv.12480  

   Reid, Andrea J. ; Carlson, Andrew K. ; Creed, Irena F. ; Eliason, Erika J. ; Gell, Peter A. ; Johnson, Pieter T. ; Kidd, Karen A. ; MacCormack, Tyson J. ; Olden, Julian D. ; Ormerod, Steve J. ; et al ( November 2018 , Biological Reviews)

   In the 12 years since Dudgeonet al.(2006) reviewed major pressures on freshwater ecosystems, the biodiversity crisis inthe world’s lakes, reservoirs, rivers, streams and wetlands has deepened. While lakes, reservoirs and rivers cover only2.3% of the Earth’s surface, these ecosystems host at least 9.5% of the Earth’s described animal species. Furthermore,using the World Wide Fund for Nature’s Living Planet Index, freshwater population declines (83% between 1970 and2014) continue to outpace contemporaneous declines in marine or terrestrial systems. The Anthropocene has broughtmultiple new and varied threats that disproportionately impact freshwater systems. We document 12 emerging threatsto freshwater biodiversity that are either entirely new since 2006 or have since intensified: (i) changing climates; (ii)e-commerce and invasions; (iii) infectious diseases; (iv) harmful algal blooms; (v) expanding hydropower; (vi) emergingcontaminants; (vii) engineered nanomaterials; (viii) microplastic pollution; (ix) light and noise; (x) freshwater salinisation;(xi) declining calcium; and (xii) cumulative stressors. Effects are evidenced for amphibians, fishes, invertebrates, microbes,plants, turtles and waterbirds, with potential for ecosystem-level changes through bottom-up and top-down processes.In our highly uncertain future, the net effects of these threats raise serious concerns for freshwater ecosystems. However,we also highlight opportunities for conservation gains as a result of novel management tools (e.g. environmental flows,environmental DNA) andmore »specific conservation-oriented actions (e.g. dam removal, habitat protection policies, managedrelocation of species) that have been met with varying levels of success. Moving forward, we advocate hybrid approachesthat manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity andecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gapbetween the aspirations of conservation biologists and the accelerating rate of species endangerment.« less
4. Tropical savanna small mammals respond to loss of cover following disturbance: A global review of field studies

   https://doi.org/10.3389/fevo.2023.1017361  

   Bergstrom, Bradley J. ; Scruggs, Samuel B. ; Vieira, Emerson M. ( February 2023 , Frontiers in Ecology and Evolution)

   Small-mammal faunas of tropical savannas consist of endemic assemblages of murid rodents, small marsupials, and insectivores on four continents. Small mammals in tropical savannas are understudied compared to other tropical habitats and other taxonomic groups (e.g., Afrotropical megafauna or Neotropical rainforest mammals). Their importance as prey, ecosystem engineers, disease reservoirs, and declining members of endemic biodiversity in tropical savannas compels us to understand the factors that regulate their abundance and diversity. We reviewed field studies published in the last 35 years that examined, mostly experimentally, the effects of varying three primary endogenous disturbances in tropical savanna ecosystems—fire, large mammalian herbivory (LMH), and drought—on abundance and diversity of non-volant small mammals. These disturbances are most likely to affect habitat structure (cover or concealment), food availability, or both, for ground-dwelling small mammalian herbivores, omnivores, and insectivores. Of 63 studies (included in 55 published papers) meeting these criteria from the Afrotropics, Neotropics, and northern Australia (none was found from southern Asia), 29 studies concluded that small mammals responded (mostly negatively) to a loss of cover (mostly from LMH and fire); four found evidence of increased predation on small mammals in lower-cover treatments (e.g., grazed or burned). Eighteen studies concluded a combination of food-more »and cover-limitation explained small-mammal responses to endogenous disturbances. Only two studies concluded small-mammal declines in response to habitat-altering disturbance were caused by food limitation and not related to cover reduction. Evidence to date indicates that abundance and richness of small savanna mammals, in general (with important exceptions), is enhanced by vegetative cover (especially tall grass, but sometimes shrub cover) as refugia for these prey species amid a “landscape of fear,” particularly for diurnal, non-cursorial, and non-fossorial species. These species have been called “decreasers” in response to cover reduction, whereas a minority of small-mammal species have been shown to be “increasers” or disturbance-tolerant. Complex relationships between endogenous disturbances and small-mammal food resources are important secondary factors, but only six studies manipulated or measured food resources simultaneous to habitat manipulations. While more such studies are needed, designing effective ones for cryptic consumer communities of omnivorous dietary opportunists is a significant challenge.« less
5. Comparing the reliability of relative bird abundance indices from standardized surveys and community science data at finer resolutions

   https://doi.org/10.1371/journal.pone.0257226  

   Feng, Mei-Ling Emily ; Che-Castaldo, Judy ( September 2021 , PLOS ONE)

   Silva, Daniel de (Ed.)

   Biodiversity loss is a global ecological crisis that is both a driver of and response to environmental change. Understanding the connections between species declines and other components of human-natural systems extends across the physical, life, and social sciences. From an analysis perspective, this requires integration of data from different scientific domains, which often have heterogeneous scales and resolutions. Community science projects such as eBird may help to fill spatiotemporal gaps and enhance the resolution of standardized biological surveys. Comparisons between eBird and the more comprehensive North American Breeding Bird Survey (BBS) have found these datasets can produce consistent multi-year abundance trends for bird populations at national and regional scales. Here we investigate the reliability of these datasets for estimating patterns at finer resolutions, inter-annual changes in abundance within town boundaries. Using a case study of 14 focal species within Massachusetts, we calculated four indices of annual relative abundance using eBird and BBS datasets, including two different modeling approaches within each dataset. We compared the correspondence between these indices in terms of multi-year trends, annual estimates, and inter-annual changes in estimates at the state and town-level. We found correspondence between eBird and BBS multi-year trends, but this was not consistent acrossmore »all species and diminished at finer, inter-annual temporal resolutions. We further show that standardizing modeling approaches can increase index reliability even between datasets at coarser temporal resolutions. Our results indicate that multiple datasets and modeling methods should be considered when estimating species population dynamics at finer temporal resolutions, but standardizing modeling approaches may improve estimate correspondence between abundance datasets. In addition, reliability of these indices at finer spatial scales may depend on habitat composition, which can impact survey accuracy.« less